uniform float uPixelRatio;
uniform float uSize;
void main(){
    vec4 modelPosition = modelMatrix * vec4(position, 1.0);
    gl_Position = projectionMatrix * viewMatrix * modelPosition;
    gl_PointSize = 40.0 * uSize * uPixelRatio ;
    gl_PointSize *= ( 1.0 / - ( viewMatrix * modelPosition ).z );
    
}